<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

        <style>

            div{
                width: 100px;
                height: 100px;
            }

            .box1{

            background-color: aqua;
            }
            .box2{
                background-color: blue;
                /* position: static;  默认*/
                /* position: relative; 相对于自己的位置 相对定位  */
                top: -50px;
                left: -50px;

            }

            .box3{
                background-color: brown;
            }
        </style>
</head>
<body>
    
    <div class="box1"></div>
    <div class="box2"></div>
    <div class="box3"></div>
</body>
</html>